This invention relates to a fuel supply control system for internal combustion engines, and more particularly to a system of this kind which is intended to prevent occurrence of vapor lock in the fuel feed system of the engine upon starting and at the beginning of idling operation of the engine immediately following the start of the engine.
It is generally known that when the temperature of fuel in the fuel feed system of an internal combustion engine is high, vapor lock or formation of gas bubbles in the fuel can occur to cause undesirable variation in the amount of fuel supplied to the engine, degrading the driveability of the engine and even causing engine stall. Particularly in a high temperature condition such as in summertime, vapor lock can easily occur at the start of the engine and at the beginning of idling operation of the engine immediately following the start of the engine. If vapor lock occurs at the beginning of engine idling operation, the idling speed of the engine becomes unstable to badly affect the driveability of the engine to a larger extent than when such vapor lock takes place in other operating regions of the engine.